Removing regulator on 9mm Cricket Bullpup

Hi gents

Posted this on the other forum, but in big bore section, might not get noticed for a while.

Was wondering if anyone knows how to remove the regulator from the original 9mm cricket bullpup. What I see inside is completely different from what I have in my .25 Bullpup. The regulated chamber is huge, but there is no spacer, but what looks like a thick walled tube glued inside or machined as part of the air chamber. Tried pushing it out the other end – wouldn’t budge. Any ideas?

Thank you in advance